[Coco] *COOL* Look what I found! (VideoMod for CoCo2)

[N8WQ]

Hi George,
Thanks for sharing that document. I will try that composite circuit and 
see how it works. It looks like the same circuit I built back in the mid 
80's on a CoCo 2.

Alan Jones

-- 
N8WQ - Canal Winchester, Ohio
http://exwn8jef.googlepages.com/home
http://n8wq.blogspot.com



George Ramsower wrote:

> http://sunpal7.mit.edu/6.111/mc6847/6847.pdf

> Here is the data sheet on the 6847. On the bottom of pp. 12 there is a 

> sample ckt for connecting the MC1372 to a composite monitor. It only 

> uses two transistors

> It's been many years since I connected a coco to a TV bypassing the RF 

> circuitry. I'm pretty certain pin 12 was where I picked up the video. 

> From there, I think I had one transistor to invert the signal and then 

> injected in the video detection point on the B&W TV set. I do remember 

> seeing pixels for the first time. The image was perfectly sharp.

>

> George

> ----- Original Message ----- From: "N8WQ" <exwn8jef at gmail.com>

> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>

> Sent: Thursday, January 08, 2009 12:27 PM

> Subject: Re: [Coco] *COOL* Look what I found! (VideoMod for CoCo2)

>

>

>> Hi Fedor,

>> Your board is clearly a "through hole" project.

>> I can see the 4 transistors, variable cap and potentiometer on the 

>> circuit board.

>> That looks like a nice project for the CoCo.

>>

>> Alan Jones

>>

>> -- 

>> N8WQ - Canal Winchester, Ohio

>> http://exwn8jef.googlepages.com/home

>> http://n8wq.blogspot.com

>>

>>

>>

>> Fedor Steeman wrote:

>>> Hi all,

>>> Well, there is definitely a little board to be added, but I do not 

>>> know the

>>> technical jargon for this technique. Of the modified CoCo2 I possess 

>>> that

>>> has this videomod, I added a range of pictures to my gallery on

>>> coco3.comfor the interested to peek at:

>>>

>>> http://coco3.com/modules.php?name=Gallery&g2_itemId=1483

>>> <http://coco3.com/modules.php?name=Gallery&g2_itemId=1483>

>>>

>>> Cheers,

>>> Fedor

>>>

>>> PS: Nobody interested in the SCART connector? :-(

>>>

>>> 2009/1/8 N8WQ <exwn8jef at gmail.com>

>>>

>>>

>>>> Hi George,

>>>> The last time I looked the Color Computer (1, 2, or 3) didn't have any

>>>> surface mount components. LOL

>>>> The circuit has 22 parts, which includes one variable capacitor and 

>>>> one

>>>> potentiometer.

>>>> If you look on page one you can read "SMD technick."

>>>> He clearly shows the circuit raised on top of the rf video modulator.

>>>>

>>>> Alan Jones

>>>>

>>>> -- 

>>>> N8WQ - Canal Winchester, Ohio

>>>> http://exwn8jef.googlepages.com/home

>>>> http://n8wq.blogspot.com

>>>>

>>>>

>>>>

>>>> George Ramsower wrote:

>>>>

>>>>

>>>>> ----- Original Message ----- From: "N8WQ"

>>>>>

>>>>>  Hi Fedor,

>>>>>

>>>>>> That looks like a SMT (surface mount) component layout. A SMT pc 

>>>>>> board

>>>>>> would have to be made or you could use what us home brewer's call 

>>>>>> "manhattan

>>>>>> style" construction. Or we could translate the project to 

>>>>>> "through hole"

>>>>>> components. It would be nice to see the schematic though. LOL

>>>>>> The BSR14 is a NPN general purpose amplifier.

>>>>>>

>>>>>> Alan Jones

>>>>>>

>>>>>>

>>>>> He's showing where on the RF modulator to make connections. The 

>>>>> ckt he

>>>>> built only has about three or four parts on it.

>>>>> Usually this mod only require a transistor to invert and amplify 

>>>>> the video

>>>>> that goes into the modulator.

>>>>> Although I can't read what he's said, it looks to me to be an 

>>>>> installation

>>>>> guide for the little ckt. This is probably why there's no 

>>>>> schematic of the

>>>>> actual ckt.

>>>>>

>>>>> George

>>>>>

>>>>>

>>>>>>

>>>>>> Fedor Steeman wrote:

>>>>>>

>>>>>>

>>>>>>> Hi all,

>>>>>>>

>>>>>>> While going through the huge lot of copied CoCo Manuals I 

>>>>>>> inherited from

>>>>>>> Michel Collette, a former Dutch CoCo-society regional 

>>>>>>> coordinator, I

>>>>>>> discovered the following schematics for making a video buffer 

>>>>>>> mod for

>>>>>>> the CoCo2, enabling a CoCo2 to be coupled up any television or 

>>>>>>> video

>>>>>>> equipment with a composite video input:

>>>>>>>

>>>>>>> http://www.steeman.dk/CoCoManuals/VideoMod_(KoenVaartjes).pdf

>>>>>>>

>>>>>>> How cool is that!?

>>>>>>>

>>>>>>> It is all in Dutch, written by someone called Koen Vaartjes, but if

>>>>>>> people

>>>>>>> are interested I could translate, clean it up, perhaps redo the

>>>>>>> schematics

>>>>>>> in a graphics editor and put it up on a webpage!

>>>>>>>

>>>>>>> Some of the equipment i inherited from Michel Collette actually 

>>>>>>> included

>>>>>>> a

>>>>>>> CoCo2 with this video mod. I tried it out when I first 

>>>>>>> discovered it and

>>>>>>> it

>>>>>>> worked flawlessly then. After having transported the CoCo one time,

>>>>>>> however,

>>>>>>> something went wrong, because after that all I got was a black 

>>>>>>> screen

>>>>>>> and no

>>>>>>> sound. I believe there must be a loose contact somewhere, 

>>>>>>> because every

>>>>>>> now

>>>>>>> and then when I try it, it works again.

>>>>>>>

>>>>>>> The final page looks like a schematic of a scart cable (

>>>>>>> http://en.wikipedia.org/wiki/Scart) that is widely used in 

>>>>>>> Europe at

>>>>>>> least.

>>>>>>> I do also have a modified SCART cable that can be used to hook 

>>>>>>> up the

>>>>>>> RGB-output of a CoCo 3 to a normal television with a scart 

>>>>>>> input. That

>>>>>>> too

>>>>>>> once worked, but not anymore. Maybe if someone could help me 

>>>>>>> understand

>>>>>>> the

>>>>>>> schematic, and figure out what wires of a RGB-cable should be 

>>>>>>> connected

>>>>>>> to

>>>>>>> what pin of the scart, I could try to fix the cable or make a 

>>>>>>> few more

>>>>>>> for

>>>>>>> anyone interested... This would mean that a CoCo3 could be 

>>>>>>> connected

>>>>>>> from

>>>>>>> the RGB output directly to a television with scart input.

>>>>>>>

>>>>>>> Cheers,

>>>>>>>

>>>>>>> Fedor

>>>>>>>

>>>>>>> -- 

>>>>>>> Coco mailing list

>>>>>>> Coco at maltedmedia.com

>>>>>>> http://five.pairlist.net/mailman/listinfo/coco

>>>>>>>

>>>>>>>

>>>>>>>

>>>>>>>

>>>>>> -- 

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>>>>>>

>>>>>>

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>>>>>

>>>>>

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